/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.flume.channel.file;

import com.google.common.collect.ImmutableSortedSet;

import java.io.IOException;

abstract class EventQueueBackingStore {
    protected static final int EMPTY = 0;
    private int queueSize;
    private int queueHead;
    private long logWriteOrderID;
    private final int capacity;
    private final String name;
    public static final String BACKUP_COMPLETE_FILENAME = "backupComplete";
    protected Boolean slowdownBackup = false;

    protected EventQueueBackingStore(int capacity, String name) {
        this.capacity = capacity;
        this.name = name;
    }


    abstract void beginCheckpoint() throws IOException;

    abstract void checkpoint() throws IOException;

    abstract void incrementFileID(int fileID);

    abstract void decrementFileID(int fileID);

    abstract ImmutableSortedSet<Integer> getReferenceCounts();

    abstract long get(int index);

    abstract void put(int index, long value);

    abstract boolean syncRequired();

    abstract void close() throws IOException;

    protected abstract int getVersion();

    int getSize() {
        return queueSize;
    }

    void setSize(int size) {
        queueSize = size;
    }

    int getHead() {
        return queueHead;
    }

    void setHead(int head) {
        queueHead = head;
    }

    int getCapacity() {
        return capacity;
    }

    String getName() {
        return name;
    }

    protected void setLogWriteOrderID(long logWriteOrderID) {
        this.logWriteOrderID = logWriteOrderID;
    }

    long getLogWriteOrderID() {
        return logWriteOrderID;
    }

}
